Grading the invasive component of urothelial carcinoma of the bladder and its relationship with progression-free survival

Abstract

Although grading is valuable prognostically in pTa and pT1 papillary urothelial carcinoma, it is unclear whether it provides any prognostic information when applied to the invasive component in muscle-invasive carcinoma. The authors analyzed 93 cases of muscle-invasive urothelial carcinoma of the bladder treated with radical cystectomy for which follow-up information was available. Each case was graded using the Malmström grading system for urothelial carcinoma, applied to the invasive component. Pathologic stage, lymph node status, and histologic invasion pattern were also recorded and correlated with progression-free survival. Thirty-four cases (37%) were pT2, 40 (43%) were pT3, and 19 (20%) were pT4. Of the 77 patients who had a lymph node dissection at the time of cystectomy, 34 (44%) had metastatic carcinoma to one or more lymph nodes. The median survival for pT2, pT3, and pT4 stages was 85, 24, and 29 months, respectively (p = 0.0001). Lymph node-negative and lymph node-positive patients had a median survival of 63 and 23 months, respectively (p = 0.0001). Fifteen patients (16%) were graded as 2b and 78 patients (84%) were graded as 3. Median survival of patients graded as 2b was 34 months compared with 31 months for patients graded as 3 (p value not significant). Three invasive patterns were recognized: nodular (n = 13, 14%), trabecular (n = 39, 42%), and infiltrative (n = 41, 44%). The presence of any infiltrative pattern in the tumor was associated with a median survival of 29 months, compared with 85 months in tumors without an infiltrative pattern (p = 0.06). Pathologic T stage and lymph node status remain the most powerful predictors of progression in muscle-invasive urothelial carcinoma. In this group of patients histologic grade, as defined by the Malmström system and as applied to the invasive component, provided no additional prognostic information. An infiltrative growth pattern may be associated with a more dismal prognosis.